Therapeutic Effect of Kidney Tubular Cells-Derived Conditioned Medium on the Expression of MicroRNA-377, MicroRNA-29a, Aquapurin-1, Biochemical, and Histopathological Parameters Following Diabetic Nephropathy Injury in Rats

BACKGROUND: Diabetic nephropathy (DN) is a critical complication of diabetes mellitus. This study evaluates whether administration of conditioned medium from kidney tubular cells (KTCs-CM) has the ability to be efficacious as an alternative to cell-based therapy for DN. MATERIALS AND METHODS: CM of rabbit kidney tubular cells (RK13; KTCs) has been collected and after centrifugation, filtered with 0.2 filters. Four groups of rats have been utilized, including control, DN, DN treated with CM, and sham group. After diabetes induction by streptozotocin (50 mg/kg body weight) in rats, 0.8 ml of the CM was injected to each rat three times per day for 3 consecutive days. Then, 24-h urine protein, blood urea nitrogen (BUN), and serum creatinine (Scr) have been measured through detection kits. The histopathological effects of CM on kidneys were evaluated by periodic acid–Schiff staining and the expression of microRNAs (miRNAs) 29a and 377 by using the real-time polymerase chain reaction. The expression of aquapurin-1 (AQP1) protein was also examined by Western blotting. RESULTS: Intravenous injections of KTCs-CM significantly reduced the urine volume, protein 24-h, BUN, and Scr, decreased the miRNA-377, and increased miRNA-29a and AQP1 in DN treated with CM rats. CONCLUSION: KTCs-CM may have the potential to prevent kidney injury from diabetes by regulating the microRNAs related to DN and improving the expression of AQP1.